1. Field of the Invention
The present invention relates to a composite resin material composed of a crosslinking polyurethane resin or a hydrolysis product thereof and one kind of a reactive resin, a nonreactive resin and a polymer alloy thereof, and a method of forming the above-described composite resin material.
2. Description of Related Art
Recently, as the earth environment has become worse, construction of such a society as to protect the earth environment has been demanded In order to reduce an environmental load and use resources effectively, recycling of resin waste has been investigated.
For example, recycling of resin parts of motor vehicles has been investigated variously. In particular, recycling of resin bumpers which are large-sized exterior parts of motor vehicles has been investigated earnestly.
The resin bumpers are generally composed of polypropylene resin and polyurethane resin. Polypropylene resin is a remeltable thermoplastic resin and can be recycled by remolding polypropylene waste, whereas polyurethane resin is a thermosetting resin which defines an insoluble and unmeltable molecular framework due to crosslinking reaction To recycle polyurethane resin, it must be subjected to some treatments.
Methods of recycling resin bumpers composed of polyurethane resin include a method of decomposing polyurethane resin to original raw materials by a chemical treatment such as glycolysis, aminolysis or hydrolysis (chemical recycling), a method of burning polyurethane resin and recovering thermal energy therefrom (thermal recycling), and a method of cutting and/or pulverizing polyurethane resin to be recycled as a packing, a filler, a levelling material, a sound absorption material, a vibration damping material or the like, or compression molding polyurethane resin together with a binder to be recycled as substitutes for rubber parts (material recycling).
In the above-described material recycling of mixing polyurethane resin bumper waste into a resin material or the like, to prevent problems such as deterioration of the material properties and surface quality resulting from inhomogeneously dispersing of additives, it is important to enhance the mixing properties of these materials. To this end, the polyurethane resin bumper waste must be pulverized into fine particles.
Japanese patent application laid-open No. Sho 50-154379 discloses a technique of pulverizing a polyurethane foam scrap, nixing the pulverized scrap with a thermoplastic resin, and injection or extrusion molding a resultant mixture.
Japanese patent application laid-open No. Sho 57-45026 discloses a technique of pulverizing thermosetting polyurethane resin waste to have a particle diameter of 1 mm orless, kneading the pulverized waste with a thermoplastic polyurethane resin, and thermoplastically molding the kneaded material.
Japanese patent application laid-open No. Sho 57-45027 discloses a technique of pulverizing thermosetting polyurethane resin waste to have a particle diameter of 1 mm or less, kneading the pulverized waste with a thermoplastic polyurethane resin and vinyl chloride resin, and calendering the kneaded material.
When polyurethane resin powder is mixed into a thermoplastic resin, it is important to pulverize the polyurethane resin finely for increasing the compatibility thereof. The above-described conventional techniques, however, do not include any proposal to pulverize polyurethane resin at a low cost, and accordingly, lack practicability.
And the above-described conventional techniques are merely the techniques of mechanically pulverizing a thermosetting polyurethane resin and adding the pulverized resin to a thermoplastic resin as a filler. There is no disclosure about the reaction property of the thermosetting polyurethane resin powder, structural change of the polyurethane resin due to hydrolysis, and influence on the material properties.